DC/DC converters are in widespread use today. A typical application example is the coupling of a DC power source to a rechargeable battery for charging the same via the DC/DC converter with a desired voltage.
A previous approach DC/DC converter is shown in FIG. 1. Therein, a pair of first side terminals 10 is coupled to a first side converter circuit 20, which in turn is coupled to a transformer circuit 30, which in turn is coupled to a second side converter circuit 240, which in turn is coupled to a pair of second side DC terminals 60. Via the transformer circuit 30, galvanic isolation between the pair of first side DC terminals 10 and the pair of second side terminals 60 is achieved.
Both of the first side converter circuit 20 and the second side converter circuit 240 comprise an H bridge circuit. Each H bridge circuit comprises four switching elements. Each switching element is depicted to have a switch and a reverse directed diode in parallel.
In a case where power is transferred from the pair of second side DC terminals 60 to the pair of first side DC terminals 10, power is transferred in two different power transfer states. As the power flow is from the pair of second side DC terminals 60 to the pair of first side DC terminals 10, this power flow direction is also referred to as a reverse power transfer, with the two power transfer states being also referred to as reverse power transfer states. In a first power transfer state, switches 242 and 248 are closed, and a current flow through the two diodes 23 and 29 in the first side converter circuit 20 is established. In a second power transfer state, switches 244 and 246 are closed, and a current flow through the two diodes 24 and 26 in the first side converter circuit 20 is established. The DC/DC converter 2 is controlled to alternate between these two power transfer states, transferring power through the transformer circuit 30 in a galvanically isolated manner.
In previous approach DC/DC converters, the response time of the first side converter circuit with respect to the second side converter circuit entering one of the first and second power transfer states has not been satisfying. To the contrary, there have been issues with undesired voltage peaks in the first side converter circuit as a response to a switching of power transfer states in the second side converter circuit.